/*
 * Copyright (C) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "semaphore.h"

namespace utility {
void Semaphore::Wait()
{
    std::unique_lock<std::mutex> lock(mutex_);
    count_--;
    if (count_ < 0) {
        condVar_.wait(lock, [&]() -> bool { return wakeupnum_ > 0; });
        wakeupnum_--;
    }
}

bool Semaphore::TryWait()
{
    std::unique_lock<std::mutex> lock(mutex_);
    if (count_ <= 0) {
        return false;
    } else {
        count_--;
        return true;
    }
}

void Semaphore::Post()
{
    std::lock_guard<std::mutex> lock(mutex_);
    count_++;
    if (count_ <= 0) {
        wakeupnum_++;
        condVar_.notify_one();
    }
}
}  // namespace utility